Air Temperature and Density

This activity will demonstrate that cold air is more dense than warmer air and will be drawn to the bottom of a container by the force of gravity.

Time requirement: 30 minutes as an activity, 20 minutes as a demonstration.



  1. Tape the three thermometers inside one end of the tank. Tape one near the top, one in the middle, and one at the bottom of the tank.
  2. Place a large quantity of ice in the other end of the tank.
  3. Place the lid on the tank.
  4. Observe the temperature of the three thermometers.

Observation questions

  1. What were the three temperatures before the ice was added to the tank?
  2. Which thermometer first indicated a change in temperature? Why???
  3. Why are there different temperatures in the tank? Which thermometer recorded the coldest temperature and which recorded the warmest temperature?
  4. What makes the cold air sit in the bottom of the tank?
  5. What will have to happen so that the three thermometers once again record the same temperature?

Last updated: August 27, 1997
Joe Twicken /
Rob Wigand